In various environments where optical devices are used to focus on an image or object, achieving a quality image hinges on the accuracy of the focusing process. To simplify the use of some optical equipment, the technology of automatic focusing can be used. Auto-focusing is used in a variety of applications, such as in digital cameras and video cameras. Auto-focus is also used in barcode scanners, precision drafting devices, mechanical actuators, and other devices. In particular, a barcode scanner may comprise an optical grid used in the focusing process.
As used herein, the term “optical grid” may represent a linear or two-dimensional arrangement of optical elements uniformly arranged with a predetermined spacing between them. The optical grid may include light sources for emitting beams of light and light sensors for detecting the light that is reflected off of an image or transmitted through an image. The light sources and light sensors may be paired in a one-to-one ratio. The sensors can be used for distinguishing between dark-shaded or opaque portions and light-shaded or transparent portions of the optical grid.
The auto-focusing device may also include components, such as a range-finder, for calculating the distance to an object. Range-finders can utilize acoustic reflective methods, stereoscopic optical methods, time-of-flight optical methods, patterned light, and other methods known in the art. In one example, a single laser can use the principle of parallax to determine distance. From the calculated distance, a lens can be moved to a target location for auto-focusing. A need exists for controlling quickly and accurately the movement of a device (e.g., a lens) for the purpose of auto-focusing or for other similar purposes related to positioning an object at or near a target location. In this regard, any improvements in the ability to position quickly and accurately an object can be beneficial in auto-focusing technologies used for cameras, barcode scanner, and other devices that may utilize auto-focusing. The process of positioning any object at any target location quickly and accurately is desired in other fields as well.